Insights from BCC Research

A Blood Test for Irritable Bowel Syndrome May Offer Relief for Sufferers

More than 30 million Americans suffer from irritable bowel syndrome (IBS), a disorder of the intestines that has no cure. Worse, its erratic, ever-changing nature makes it difficult to identify its cause, adding to the woes of its sufferers struggling for symptomatic relief.

The causes of IBS, also known as spastic cause, have long eluded doctors. Theories abound, such as that oversensitive nerves in the intestine, intestinal muscle disorders and inflammations of the intestinal wall could all play a role. It has also been observed that IBS is more common among people who have had an intestinal infection. Some people with irritable bowel syndrome have more bacteria in their small intestine. A genetic predisposition may also play a role. Psychological stress, dietary habits and food intolerances are thought to be possible triggers too. Yet for many of these factors it is not clear whether they are a cause or result of IBS, and whether they actually contribute to the symptoms.

For the first time, researchers have identified a diagnostic test they claim can reliably identify the presence of certain forms of IBS in people. Lead author of the PLOS ONE study, Mark Pimentel, M.D., and colleagues compared over 2,000 people already believed to be suffering from diarrhea-predominant IBS (D-IBS) with people diagnosed with IBD, celiac disease, or who had no prior gastrointestinal issues. They found that their test identified cytolethal distending toxin B (CdtB), a chemical released by bacteria known to cause food poisoning, created IBS-like symptoms and its own specific antibodies with greater than 90% accuracy. These antibodies were elevated in participants with IBS compared with participants without IBS.

These biomarkers, Pimentel reports, may be helpful in distinguishing IBS from inflammatory bowel disease in the workup of chronic diarrhea. Identifying IBS often requires an exhaustive series of examinations and medications for the patient as their doctors try to rule out other conditions, often involving invasive procedures such as colonoscopies and sigmoidoscopies.

"Having a test like this shortens the time of suffering, it shortens the time of investigation and accelerates getting the patient directly to treatment," Pimentel says.

Blood test diagnostics have become an important tool for the evaluation, monitoring and screening of various conditions. The early detection of metabolic conditions and diseases can be life-saving. By using specific blood tests, health changes can be detected, screened and monitored early.